Boring-bar.



W. E. MGELDOWNEY.

BOEING BAR APPLIGATION FILED FEB. 14, 1912.

Patented May 6, 1913.

WJTNESSES:

UNITED STATES PATENT FFICE.

'WILBER MOELDOWNEY, OF DENVER, COLORADO, ASSIGNOR OF ONE-HALF TO WILLIAM H. MoAI-ONEY, OF DENVER, COLORADO.

BORING-BAR.

Patented May 6, 1913.

To all whom itmay concern Be it known that I, WILBER E. Mo-EL- DOWNEY, a citizen of the United States, residin at Denver, in the county of Denver and gtate of Colorado, have invented certain new and usefullmprovements in Boring-Bars, of which the following is a specification.

My invention relates to boring bars used in connection with lathes, boring mills, drill presses and other machines of similar character for the production of cylindrical holes in machine-parts and its object resides in the provision of a mechanism of simple construction by which the cutting tools whose ends project beyond theperipheral surface of the cylindrical bar with which they are associated, may be adjusted radially with relation to the same', for the purpose nism,

comprised in my invention,

of varying the diameter of the hole produced by the cutting action of their protruding ends upon the metal with which they are brought in engagement. The adjusting mechanism includes a graduated scale on which the degree of expansionor contraction of the boring instrument by ad- 'ustment of its cutting tools, may be readily observed and. the said mechanism is constructed'to permit a micrometrical' adjustment of the tools whereby the size of the hole produced by the action thereof may be varied to anyfdesired fraction of its diameter.

The cutting tools employed in my invention being 0 simple design do. not require the employment of special machinery in and they may for this reason he made of self-hardening, high speed steel which can be shaped only by forging and grinding. The simplicity of form of the cutting tools makes it possible to produce them of scrap-metal which is forged to the required shape and dimensions and ground upon an ordinary grinding wheel or stone. The number of cutting tools radiating from a common point in the axis of the bar, that may be adjusted through the instrumentality of one and the same mechais limited only by the circumferential dimension of the bar, the pressure exerted by the said mechanism is transmitted tothe tools in a line coincident with the axis of the bar, thus preventing binding strains, and the simplicity of all the cooperative parts not only diminishes the cost of production and maintenance but permits the employment of operatives not skilled in the special branch of machine-work to which my invention appertains.

In the accompanying drawings in the various views of which like parts are similarly designated, Figure 1' represents a side elevation, partially in section of the working end of a boring bar, Fig. 2, a longitudinal section taken along the line 2-2, Fig. 1, drawn to an enlarged scale, and Fig. 3, a slightly reduced transverse section taken along the line 3-3, Fig. 2.

Referring more specifically to the drawin s, the reference numeral 2 designates the cylindrical, axially bored, boring bar which at arbitrary distances from its forward end, is provided with radially extending slots 3 to receive the cutting tools fwhich are longitudinally slidably fitted therein. The tools 4 are made of rectangular, flat pieces of steel, the cutting ends of which project beyond the exterior surface of the bar, while their opposite inner ends which project into the bore of the bar, are provided with beveled faces 5 which extend obliquely from their end edges to their rearmost longitudinal edges. The faces 5 of the tools disposed in the slots 3 which radiate from a common point in the axis of the bar and which may vary in number within the limit of the circumferential dimension of the same, are engaged by the conical extremity of an ex- 'panding wedge 6 whose cylindrical bodyportion is movably fitted in the bore of the bar. The opposite extremity of the wedge which is likewise ofoonical form, projects into a transverse bore in the bar to be engaged by the beveled edges of two nuts 7 which are slidably fitted in'the said transverse bore and areheld against rotation by means of a key 15 disposed in a seat formed longitudinally in the wall of the same.

The nuts 7 are respectively provided with internal right-hand and left-hand screwthreads for cooperative engagement with corresponding male threads formed on a headed adjusting screw 8 which is held against longitudinal displacement by plugs 9 and 10 which are screwed into the ends of the transverse bore. The circular head 12 of the screw has a concentric exterior portion 13 of reduced diameter which occupies a central opening in the plug 1'0 which is of annular form. The head has an angular recess for the application of a key by which the screw may be turned about its axis and' it is provided upon the end surface of its reduced portion 13 with a circular series of graduations which by registration with one or more marks on the adjoining beveled edge of the annular plug 10, designate the extent of the are through which the screw is rotated, or with other words, the degree of expansion or contraction of the respective series of cutting tools.

An annular washer 14 engaging the forward edges of the tools 4, is held in place by a nut 16 screwed upon the threaded, reduced forward end of the bar 2, for the purpose of holding the said tool against lateral displacement in case the slots in which they slide are enlarged by wear.

A pin 17 screwed into a transverse opening in the reduced end of the bar, is provided to maintain the parts in place while being assembled.

When the bar is equipped with more than one series of cutting-tools, those in the series succeeding the foremost one, are held against lateral movement by a retaining key 18 whose ends extend in the slots in which the tools 4: have their movement and which at its edge opposite to that which engages the tools, has a central, oblique arcual groove which is occupied by a beveled circumferential face on a screw 19 which being longitudinally adjustably disposed in a partially threaded transverse bore in the bar, serves to drive the key against the tools and the latter against the opposite edges of the slots in which they move to take up wear.

The mechanism by means of which the second and following series of tools are expanded and contracted, is identical to that employed in connection with the foremost series and hereinbefore described,

Having thus described the mechanical construction of my improved boring-bar, it will be readily understood that by forming screw threads in the cutting edges of the tools 4:, the bar may be efiectively used for threading bores in machine parts from which, after the thread has been produced, it may be readily withdrawn by adjustment of the screw 8 to allow contraction of the, tools. The boring bar may also be used to advantage as an expanding reamer, thereby obviating the necessity of double boring to enlarge a hole already formed.

Having thus described my invention what I claim and desire to secure by Letters-Patent is:

1. In a device of the class described, a bar having an axial opening and slots extend ing radially from a common point in its axis, cutting-tools movable in said slots and having beveled faces at their inner ends, a wedge whose opposite ends are cone-shaped, movable in said opening to engage the beveledfaces on said tools at one of its ends, driving members movable in a transverse opening in said bar, in engagement with the opposite end of said wedge, and means for moving said members simultaneously in opposite directions toward the said wedge.

2. In a device of the class described, a bar having an axial opening and slots extending radially from a common point in its axis,

cutting-tools movable in said slots and having beveled faces at their inner ends, a wedge, whose opposite ends are cone-shaped, movable in said opening to engage the beveled faces on said tools at one of its ends, nuts slidable in a transverse opening in said bar, and respectivelyprovided with righthand and 1eft-hand screw-threads, and an adjusting screw rotatable in said transverse opening and having threads in cooperative. engagement with those on the nuts.

3. In a device of the class described, a bar having an axial opening and slots extending radially from a common point in its axis, cutting tools movable in said slots and having beveled faces at their inner ends, a wedge movable in said opening, in enga ement with said beveled faces, means for e ecting a movement of said wedge whereby to adjust the position of said tools relative to the axis of the bar, and adjustable means for holding said tools against displacement in the direction of said. axis, including a key in engagement with said tools, and a screw rotatable in a transverse opening in said bar and having a beveled portion in engagement with a corresponding face on said key,

4. In a device of the class described, a bar having an axial opening and slots radiating from its axis, cutting tools movable in said slots and having beveled faces at their inner ends, a wedge engaging said faces, a nut slidable in a transverse opening in said bar in driving engagement with said wedge, and a screw rotatably mounted in threaded engagement with said nut.

In testimony whereof I have affixed my signature in presence of two witnesses.

' WILBER E. MQELDOWNEY.

Witnesses:

G. J. ROLLANDET, L. Rnoanns, 

